Soluble coffee, also referred to as instant coffee, is a convenient alternative to the more traditional roast and ground coffee (R&G). Instant coffees, however, often trade the robust flavor of the R&G bean for the convenience of quick preparation. Soluble coffee is typically made by extraction and thermal hydrolysis of roast and ground (R&G) coffee, followed by separation and drying of the extract. Often soluble coffees may have an imbalanced flavor and aroma due to the high degree of processing and associated losses. The high temperatures and pressures used in such processes often produce a lesser quality product as compared to traditional R&G coffee.
The inferior quality of the soluble coffees has been a longstanding problem. U.S. Pat. No. 5,576,044 (Nov. 19, 1996) provides an emulsion preconcentrate which contains hydrolyzed coffee oil and a coffee aroma. Coffee oil is hydrolyzed using, for example, alkaline hydrolysis using a conventional saponification process for fats and oils. The hydrolyzed oils generally have melting points greater than about 30° C. After adding the appropriate coffee aroma, the emulsion preconcentrate is added to soluble coffee particles (e.g., instant coffee). Once the coffee beverage is prepared, a “[s]mall amount of oil may appear on the surface, particularly if the hydrolyzed oil contains high levels of glycerides or the soluble coffee product contains unhydrolyzed oil. However, the amount of oil on the surface is well within acceptable ranges; for example equivalent to or less than that which would appear on the surface of roast and ground coffee.”
U.S. Pat. No. 4,044,162 (Aug. 23, 1977) provides a method of improving the flavor and aroma of decaffeinated coffee by contacting green coffee with sucrose during the caffeine extraction process. The sucrose is reported to replace natural sucrose removed or destroyed during caffeine extraction.
U.S. Pat. No. 4,857,351 (Aug. 15, 1989) provides a method for treating coffee beans to improve flavor and aroma. One step in this process involves the treatment of partially roasted coffee beans with an alkaline solution at a temperature of about 4 to about 177° C.; a sugar can be added to the solution.
U.S. Pat. No. 6,291,006 (Sep. 18, 2001) provides a so-called dissolution agent that can be added to coffee and other beverages. The dissolution agent preferably includes lecithin, propylene glycol, ethoxylated mono and diglycerides, and a sucrose fatty acid ester, combined with maltodextrin and water to make a binder solution. The dissolution agent is added to the beverage product normally at a level of about 0.2 to about 0.33 percent.
There remains a need to provide an improved and more efficient method of producing soluble coffee that retains the robust coffee flavor and aroma similar to R&G coffee. There also remains a need to provide improved soluble coffee containing higher levels of coffee oils which, when prepared, do not form visible “oil-slicks.”